Red Flags Emerge in World’s Top Stocks as Korea Volatility Soars

Bets for South Korean stock swings have surged, raising concerns over the rally in this year’s best-performing market.

The Kospi 200 Volatility Index has jumped to levels last seen during the April market swoon triggered by Donald Trump’s tariffs. The spike marks a rare departure from the relative calm elsewhere, with the VKOSPI now hovering around its widest spread versus the Cboe Volatility Index since 2004. The Korean gauge of expected swings slipped on Wednesday as the benchmark Kospi index climbed for a third day.

With a 73% rally this year, the Kospi is heading for its biggest ...